Use of speleotherapy in patients with post-COVID-19 syndrome

Background The post-COVID-19 syndrome (PCS) is characterized by persistent or newly developed symptoms and performance deficits lasting at least 3 months following SARS-CoV-2 infection, with dyspnea as a common symptom. Speleotherapy, a form of climatotherapy utilizing the microclimatic conditions of natural or artificial caves, has been proposed as a supportive treatment for chronic airway diseases, potentially improving lung function and exercise tolerance.Methods This study investigated the short-term effects of speleotherapy on lung diffusion capacity (DLCO) in PCS patients through a prospective interrupted time-series analysis. Forty-six patients (51.9 +/- 9.3 years; 43% female) referred for rehabilitation were included, with a history of COVID-19 infection and persistent deficits lasting over 3 months. Patients underwent spirometric assessments of DLCO repeatedly on days without speleotherapy intervention and on days with intervention, alongside subjective symptom evaluations using the Nijmegen questionnaire.Results PCS patients performed a median of four out of seven speleotherapy sessions during rehabilitation, resulting in a total of 388 measurements. Analysis revealed no significant changes in DLCO or related parameters (transfer coefficient (KCO), inspiratory volume (IV), total lung capacity (TLC), Residual volume (RV)) during rehabilitation and between speleotherapy and control days (p >= 0.544). Subgroup analysis of patients with DLCO below 80% of predicted reference and symptom severity assessments also revealed no therapeutic benefits. Speleotherapy frequency showed no dose-dependent effects on pulmonary outcomes (p = 0.171). Findings from a small control group confirmed these results (p >= 0.997).Conclusion Speleotherapy did not improve DLCO or alleviate symptoms in PCS patients within this study cohort. Further research is needed to investigate whether speleotherapy can alleviate pulmonary dysfunction in different PCS populations.